Radiophotoluminescence phenomenon in copper‐doped aluminoborosilicate glass

Abstract

Radiophotoluminescence phenomena have been widely investigated on various types of materials for dosimetry applications. We report that an aluminoborosilicate glass containing 0.005 mol% copper exhibits intense photoluminescence in the visible region induced by X‐ray and γ‐ray irradiation. The luminescence is assigned to the 3d94s1 → 3d10 transition of Cu+. The proportionality of the intensity of the induced photoluminescence to the irradiation dose was confirmed up to 0.5 kGy using 60Co γ‐ray irradiation. Based on the spectroscopic results, a potential mechanism was proposed for the enhancement of the photoluminescence. The exposure to the ionizing radiation generates electron‐hole pairs in the glass, and the electrons are subsequently captured by the Cu2+ ions, which are converted to Cu+ and emit the luminescence. For the glass containing 0.01 mol% copper, the pronounced enhancement of the photoluminescence was not observed because the reverse reaction, ie, the capture of the holes by the Cu+ ions, becomes prominent. The photoluminescence induced by the irradiation was stably observed for the glasses kept at room temperature and even for the glasses heat‐treated at 150°C. However, the induced photoluminescence could be eliminated by the heat treatment at a temperature at 500°C, and the glass returned to the initial pre‐irradiation state. The Cu‐doped aluminoborosilicate glass is a potential candidate for use in dosimetry applications.

Research Progress of Radio-photoluminescence Materials and Their Applications

“…事实上，有关 Cu 离子掺杂材料的辐射发光现 象早已被广泛研究，不过多集中在 TSL、OSL 和闪 烁发光，基于 RPL 特性的研究有限 [42] 。大多数 Cu 离子掺杂体系的 RPL 材料能够显示良好的化学耐 久性，但由于较低的辐射探测灵敏度，并不适用于 个人剂量监测，但在大剂量监测方面具有较大的应 用潜力。 Hashikawa 等 [42] (a) Schematic diagram of RPL/OSL/TSL general luminescence mechanism [13] ; (b) Excitation and emission spectra of Ag-PG [7] ; (c) Emission spectrum of Ag-PG under different doses of X-ray irradiation [52] ; (d) Excitation spectrum (pink dotted line) and emission spectrum of Ag-Rb glass before and after X-ray (10 Gy) irradiation [54] ; (e) Emission spectra of Ag-Nd co-doped phosphate glass at different radiation doses (310 nm excitation) [55] ; (f) Excitation spectrum (dashed line) and emission spectrum (solid line) of Ag-doped CsCl before and after X-ray irradiation [59] ; (g) Excitation and emission contour spectra of Al2O3:C,Mg irradiated by β-rays ( 90 Sr/ 90 Y) [63] ; (h) Excitation spectrum and emission spectrum of LiF after X-ray irradiation (126 Gy) [64] ; (i) RPL defect center in LiF, where F3 + is formed by three anionic vacancies capturing two electrons and F2 is formed by two anionic vacancies capturing two electrons [7] 随后， Hashikawa 等 [66] [68] 。Sm 离子是目前研究最多的镧系元 素， Sm 离子掺杂体系的 RPL 特性于 21 世纪初被发 现，但最初并没有用于辐射剂量学，而是用于高密 度的光学存储器 [7] 。直到 2011 年，Okada 等 [69][70] 才 将 Sm 离子掺杂材料用于 X 射线微束的剂量分布检 测。基于 Sm 离子掺杂的 RPL 材料体系有许多，主 要包括氟磷酸盐、氧化物、氟氧化物和卤化物等， 但实际只有少部分能够表现出 RPL 特性。特别需要 指出的是，Sm 离子掺杂材料具有极大的剂量范围 (mGy~kGy)，且大部分材料具有较好的辐射灵敏度 和可循环使用性等特点 [32,34,71] 。此外，Sm 离子掺 杂材料记录的 RPL 信号极其稳定，几乎不会衰退。 同时，辐照后产生的 RPL 信号具有极短的积聚时间， 因此适用于辐射剂量的实时监测。在 Sm 离子体系 的化合物中， Sm 离子在二价和三价下均具有稳定的 氧化态，但它们却拥有不同的电子架构。基态下的 [7,32,72]…”

Optical Characterization of Phosphate Glass with Additional Aluminum/Tin Impurities

“…Previously, we reported copper activators in PG, (12) and those impurities might work as activators for different fluorescence functions. (13,14) Although different energy levels are often expected to be demonstrated for other activators, they might cause a fluorescence competition if the phosphates capture the impurities that act as activators in the glass substrate.…”

Ag Concentration Dependence of Build-up Effect of Radio-photoluminescence in Ag-doped P2O5–Al2O3–Na2O–SiO2 Glasses

“…Thus, the RPL intensity can be repeatably read out, making it advantageous over TSL and OSL. (4) Phosphors exhibiting RPL include Ag-doped phosphate glasses, (5) Cu-doped glass, (6,7) Al 2 O 3 :C,Mg, (8) Eu-doped materials, (9,10) Sm-doped materials, (11,12) Yb-doped NaCl, (13) and LiF, (14,15) MgF 2 , (16) CaF 2 , (17,18) Mg 2 SiO 4 , (19) CaSO 4 , (20) K 2 CO 3 , (21) and Na 2 CO 3 . (22) The phosphors exhibiting RPL of greatest interest are currently Ag-doped phosphate glasses.…”